Felicia McMullen has lived in the energy-efficient Devine Legacy apartment building in central Phoenix since December.

Courtesy of Mica Thomas Mulloy

It's been a record hot summer in many cities across the nation. Phoenix is no exception. This Sonoran Desert metropolis already records more days over 100 degrees than any other major U.S. city. Now, climate models predict Phoenix will soon get even hotter.

A hotter future may mean a more volatile environment — and along with it, natural disasters, greater pressure on infrastructure, and an increased physical toll on city residents.

While some city planners around the country discuss ways to mitigate climate change, planners in Phoenix assume that change is already under way. Now, they are working to prepare the Phoenix metro area, and its approximately 4 million residents, for a new reality.

'How Are We Gonna Live Here?'

The view is bleak from John Larsala's front drive in West Phoenix. The tree in front of the house is dead, and the grass is dead, too. In fact, there's no grass at all anymore.

On a household income of $18,000 a year, Larsala can't afford the water charges required to keep his yard green. "All these trees are dying, because I can't put water on it," he says.

So Larsala's children and their friends play basketball in the barren yard. That is, until June comes around and the blazing Phoenix summer finally forces everyone inside.

For three months, Larsala will shut the doors and windows tight. To save money, he soaks his kids in a cool bath and delays using the air conditioning until just before bedtime.

"Whether you are inside or whether you are outside, the heat costs you money," Larsala says.

When told that climate scientists predict the state will get even hotter in the future, Larsala is taken aback.

"It's going to be hotter than what it is right now? Who gonna live here? How are we gonna live here?"

Sustained Heat Waves Ahead

Phoenix actually suffers from two heat problems. One is a product of growth. Desert nights don't cool down they way they used to, because energy from the sun is trapped in roads and buildings, a phenomenon researchers call the "urban heat island effect."

As Phoenix grows, so does the problem, says Nancy Selover, the state climatologist.

"We keep thinking we'll probably see a night when we only get down to 100 as a minimum temperature, which is kind of shocking," Selover says.

Standing outside in a low-income neighborhood near Phoenix, Selover points out that many households here are using "swamp coolers," or evaporative coolers. These cooling units are cheaper than air-conditioning — but they're also less effective.

Phoenix's second problem comes from global climate change. Researchers predict it will make droughts longer and temperatures higher in the region.

Data from the North American Regional Climate Change Assessment Program predict sustained heat waves above 114 degrees will be a yearly crisis in Phoenix by 2040. And each one, researchers project, will last a sweltering three weeks.

A Laboratory For What Works

Selover says these coming changes present Phoenix with an opportunity.

"As a desert city, Phoenix is kind of a laboratory for us to figure out what works and what doesn't work, to try to mitigate those things."

In the future, Selover says, "we may well have to live differently."

Now, city officials are starting to think about what that new lifestyle might entail. One idea is to cover 25 percent of Phoenix with shade trees.

But some, like architect John Meunier, arguefor much greater lifestyle adaptations.

Meunier studies pre-industrial desert cities around the world, looking for lessons to apply in modern desert cities like Phoenix.

Sitting at a light-rail stop downtown, he says creating sustainable futures in cities like this one has"everything to do with managing without having to use a lot of extra energy and power."

To do that, Meunier says planners could encourage 10 times as many people to live around Phoenix's light-rail stations. Getting more use out of the system would take cars — and heat — off the street.

These people would also live in taller buildings. Meunier says desert cities in Yemen, for example, take advantage of tall buildings to shade narrow streets.

"It's crucially important. I mean, not being exposed to the direct sun's rays makes a great big difference," he says.

It's the way Phoenix has been built, Meunier says, that will make its residents vulnerable to rising temperatures.

"I'm not arguing that we should all live at a higher density," Meunier says. "What I am arguing is that there's a lot to be gained by having more of us live at higher density."

Learning To Build Better

For Meunier's ideas to become reality, developers will have to make the choice to build differently.

Some of them already have. Take the city's light rail north about three miles, and you can get a close-up view of how buildings like Meunier envisions might actually work.

The Devine Legacy is a housing complex designed for people with lower incomes. Right next to the rail line, every window is dual-paned, and the building is also superinsulated. Together, those features make a typical Devine Legacy unit 40 percent more energy efficient.

Walking through the front gate leads you to a courtyard. Four-story buildings rise up on either side of you. There's shade everywhere, and a breeze moves through the space. Even on a 113-degree day in Phoenix, it feels much cooler.

"Having a cool place to live is more important to me than food," says resident Felicia McMullen.

Before she moved here, McMullen says she was sick and stressed. She sometimes spent $300 a month to cool her suburban home.

Now, McMullen says, "I don't have that problem." Her last electric bill was $60 — and the stress is gone.

Ernesto Fonseca, a planner who specializes in sustainable communities, helped test Devine Legacy's energy use before it opened late last year.

He considers the complex a small victory in what may someday be a more complicated effort to stay cool.

"People in extreme climates learn to live with it," Fonseca says. "And that's part of a resilient society."

Fonseca thinks a lot about this idea of resilience. He says it means that people who live in Phoenix must do more than try to solve the causes of escalating temperatures — they must also learn to withstand the changes as they happen.

Because, as Fonseca says, "We don't have a choice."

Peter O'Dowd works with the public radio collaborative Fronteras. Read more from their series "Heat Wave."

I'm Melissa Block. And we begin this hour with the latest from the NPR Cities Project.

(SOUNDBITE OF STREET NOISE)

BLOCK: This week and next, we're reporting on how cities are treating climate change as a reality. Today, we head to Phoenix, Arizona where it is uncommonly hot, even for August, in the desert city. Temperatures have topped 110 degrees for most of the past week and five of those days broke records. We asked a few people in Phoenix today how they're trying to stay cool.

UNIDENTIFIED WOMAN #1: I carry around this cup and I normally fill it with ice and then water. That keeps me cool. Sometimes I'll put it on my pressure points.

UNIDENTIFIED WOMAN #2: Well, I try to, first of all, stay in the shade and second of all, try to spend as much time in buildings during the heat peaks.

BLOCK: That was Marguerita Sedova(ph), William Kennedy(ph) and Jane Stephans(ph) on how to beat the heat in Arizona. Scientists say this summer's record temperatures are likely the result of a changing climate. And in most city halls, there's talk of sustainability and trying to mitigate the change.

CORNISH: But increasingly, there's talk of a new watch word, resilience. City planners expect a more volatile environment, so they're working on how to adapt, how to survive.

BLOCK: Today, what the means in the Sonoran desert. Here's Peter O'Dowd of member station KJZZ.

PETER O'DOWD, BYLINE: Here in John Larsala's driveway the view is bleak.

JOHN LARSALA: You see our tree is dead.

O'DOWD: The grass is dead, too. In fact, there is no grass anymore.

LARSALA: All these trees are dying because I can't put water on there.

O'DOWD: Larsala can't afford the water on a household income of $18,000 a year. His children and their friends play basketball in the barren yard. But once summer hits, you're more likely to find them inside. From July through September, Larsala keeps the doors and windows shut tight. To save money, he'll soak his kids in a cool bath and delay using the air conditioning until just before bedtime.

LARSALA: Whether you are inside, whether you are outside, the heat costs you money.

O'DOWD: Let me ask you how you feel about this. Climate scientists say that Arizona's going to get hotter. You just - the look on your face was of surprise.

LARSALA: Yes. It's going to be hotter than what it is right now? Who gonna live here? How are we gonna live here?

O'DOWD: Phoenix actually suffers from two heat problems. Desert nights don't cool down they way they used to because energy from the sun is trapped in roads and buildings. Researchers call this the urban heat island effect. As Phoenix grows, so does the problem.

NANCY SELOVER: We keep thinking we'll probably see a night when we only get down to 100 as a minimum temperature, which is kind of shocking.

O'DOWD: Nancy Selover is the state climatologist. We're standing outside in a low-income neighborhood near Phoenix.

SELOVER: There are swamp coolers on most of these houses and some of them probably don't have air conditioning.

O'DOWD: Swamp or evaporative coolers are cheaper than air-conditioning, but they're also less effective.

SELOVER: It's going to be pretty unbearable.

O'DOWD: And potentially deadly. Second, researchers predict climate change will make droughts longer and temperatures higher. Data from the North American Regional Climate Change Assessment Program predict that by 2040, sustained heat waves above 114 degrees will be a yearly crisis in Phoenix, each one lasting a sweltering three weeks.

SELOVER: As a desert city, Phoenix is kind of a laboratory for us to be able to figure out what works and what doesn't work and try to mitigate those things.

O'DOWD: Do you think we'll have to live differently?

SELOVER: We may well have to live differently.

O'DOWD: And how that might happen is something city officials are starting to think about. One idea is to cover 25 percent of Phoenix with shade trees. But some argue for much greater lifestyle adaptations. Architect John Meunier studies pre-industrial desert cities around the world and he brings their lessons here to a stop along the light rail near downtown.

The number one thing that these older cities could teach us in a new desert city like Phoenix, what is it?

JOHN MEUNIER: Well, I think it's everything to do with managing without having to use a lot of extra energy and power.

O'DOWD: To do that, Meunier says planners could encourage 10 times as many people to live around this train station. Getting more use out of light rail would take cars and heat off the street. These people would also live in taller buildings. Meunier says desert cities in Yemen, for example, take advantage of tall buildings to shade narrow streets.

MEUNIER: That's crucially important. I mean, not being exposed to the direct sun's rays makes a great big difference.

O'DOWD: Instead of exposed front yards and backyards, older desert cities employ well-ventilated courtyards. Mediterranean cities paint roads and rooftops white to reflect the sunlight. Meunier says it's the way we've built Phoenix that will make us vulnerable.

MEUNIER: I'm not arguing that we should all live at a higher density. What I am arguing is that there's a lot to be gained by having more of us live at higher density.

O'DOWD: All right. So I'm going to leave John Meunier behind and jump on the light rail here and take it north about three miles. I want to show you how this type of building might actually work because for Meunier's ideas to become reality, developers will have to make the choice to build differently. And in some cases, they already have.

And here we are at Devine Legacy. It's a housing complex that's designed for people with lower incomes and it's right next to the rail line. Every window is dual-paned, and the building is also superinsulated, which means the typical apartment at Devine Legacy is about 40 percent more energy efficient. Now, if you go through this gate you'll emerge into a courtyard.

Four-story buildings rise up on either side of you. There's shade everywhere, and a breeze moves through. Even on a day when it's 113 degrees in Phoenix, it doesn't really feel like it.

FELICIA MCMULLEN: Having a cool place to live is more important to me than food.

O'DOWD: Before Felicia McMullen moved here, she says she was sick and stressed. She sometimes spent $300 a month to cool her suburban home. Now...

MCMULLEN: I don't have that problem.

O'DOWD: Her last electric bill was $60. The stress is gone.

ERNESTO FONSECA: People in extreme climates learn to live with it, you know, and that's part of a resilient society.

O'DOWD: Ernesto Fonseca helped test Devine Legacy's energy use before it opened late last year. The idea of resilience is something he thinks about. It means that people who live in Phoenix must do more than try to solve the cause of escalating temperatures, they must also withstand the changes as they happen.

FONSECA: We don't have a choice.

O'DOWD: That's why he considers this complex a small victory in what may someday be a more complicated effort to stay cool. At 4570 North Central Avenue in Phoenix, Peter O'Dowd for the NPR Cities Project. Transcript provided by NPR, Copyright NPR.